During the past several years, the anthracyclines, most notably adriamycin, daunomycin and carminomycin have emerged as important chemotherapeutic agents because of their antimicrobial activity, and because of their activity against a broad spectrum of human cancers. The products are presently produced by fermentation. However, extensive efforts have been made to develop a totally synthetic route which would permit the practical production of the compounds by chemical means and also open the pathway for the production of potentially more useful analogs.
The efforts have principally been directed toward the preparation of adriamycinone, daunomycinone, carminomycinone and other sugar free analogs since procedures for the substitution of L-daunosamine at the seven positions of the anthracycline ring are well known. Such methods as have been developed however have been plagued with difficulty, principally due to the opportunities for the production of unwanted and inactive regio- or stereo isomers. As a result, the overall yields have been unacceptably low.